The flight instructor reported that the purpose of the flight was to conduct commercial maneuvers in the local area. After completing maneuvers in the practice area, the airplane went to the airport to conduct takeoff and landings. The student pilot reported that during the third landing, he did his landing checklist about midfield on the downwind. After he put the landing gear handle down, he noted that he heard the landing gear hydraulic motor actuating. He added that he glanced at the gear down indictor light and believed that it was green. During the touchdown the right main landing gear collapsed, and the airplane came to a stop on the runway. After exiting the airplane, the flight instructor and student pilot noticed that the landing gear handle was down, the green gear down light was not illuminated, and the circuit breaker for the gear pump was open. The airplane sustained substantial damage to the empennage. During a postaccident examination, the airplane was lifted up by jacks and the landing gear was swung 5 times. The malfunction could not be reproduced, and no anomalies were noted.